The deputy prime minister, Nick Clegg, announced a major increase in aid to Pakistan today as the country struggles to cope with the devastation caused by the floods.

He told the Liberal Democrat conference the UK will be "dramatically increasing" the amount of money going to Pakistan beyond the £60m already provided.

The money will provide temporary school facilities, help farmers replace livestock and crops and provide more support for the emergency efforts in southern Pakistan.

Clegg said he feared the "worse is still to come" for Pakistan after visiting the flood-stricken country.

"I've never seen anything like it. I found it deeply, deeply, personally, a very shocking experience because the scale is just really difficult to comprehend," he said.

Answering questions from party activists at the conference in Liverpool, Clegg said: "This is a terrible catastrophe which is getting worse, not least because of the deathly grip of waterborne diseases."

He added: "We will be dramatically increasing the amount of government aid that we are giving, even on top of what we have already provided, on top of the £60m we have already provided, for three things.

"Firstly, to provide temporary education facilities for children in camps and elsewhere. Secondly, to help farmers replenish livestock and have the ability to replant where they can replant and thirdly, to provide even further significant support in the emergency effort in the south where the crisis is most acute."

The international development secretary, Andrew Mitchell, is in New York for a donors' meeting today and Clegg, who has been heavily involved in the aid effort, will fly out tomorrow.

"It's a catastrophe the scale of which we have barely ever encountered before and I think we can be proud in the face of that catastrophe what we in Britain have done and I'm very proud that Liberal Democrats have played a big role now, and in the coming days at the United Nations at the millennium development goals summit in really pushing the rest of the world to take this as seriously as we do."